Telemicroscopic instruments are used for magnifying the work area during precision work such as microsurgery, dental work, inspection of circuit board solder joints, and assembly of miniature parts. Such instruments, typically including a pair of microscopic loupes, are adjustably mounted to an eyeglass frame or head mount by an ocular mounting assembly.
As one example, the ocular mounting assembly disclosed in U.S. Pat. No. 5,381,263 allows the mounting of a pair of ocular devices to an eyeglass frame, or head mount, and is linearly or rotationally adjustable through five degrees of freedom. An adjustable ocular support assembly with slidably extendable arms provides interpupillary distance, convergence angle and view adjustment of the ocular devices, which are rotatable attached to the support. An adjustable clamp assembly is rotatably attached to the ocular support assembly and provides height and view angle adjustment of the ocular devices. When the slidable arms of the ocular support assembly are extended, however, some rotating motion may occur, in particular with heavier oculars and with fully extended support arms. The rotating motion causes vertical misalignment, or divergence, of the axes of the ocular devices. Excessive divergence can cause eyestrain, discomfort and even headaches.